Accessory Device Architecture

ABSTRACT

An accessory device architecture is described. In one or more implementations, data is received from an accessory device at an integrated circuit of a computing device, the data usable to enumerate functionality of the accessory device for operation as part of a computing device that includes the integrated circuit. The data is passed by the integrated circuit to an operating system executed on processor of the computing device to enumerate the functionality of the accessory device as part of the integrated circuit.

RELATED APPLICATIONS

This application is a continuation of and claims priority to U.S. patent application Ser. No. 13/527,263, filed Jun. 19, 2012, entitled “Accessory Device Architecture”, which claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 61/646,799, filed May 14, 2012, the disclosure of which is hereby incorporated by reference in its entirety, this application also incorporates the following applications by reference in their entirety: U.S. patent application Ser. No. 13/470,633, filed May 14, 2012, Attorney Docket Number 336554.01, and titled “Flexible Hinge and Removable Attachment”; and U.S. patent application Ser. No. 13/471,186, filed May 14, 2012, Attorney Docket Number 336563.01, and titled “Input Device Layers and Nesting”.

BACKGROUND

Mobile computing devices have been developed to increase the functionality that is made available to users in a mobile setting. For example, a user may interact with a mobile phone, tablet computer, or other mobile computing device to check email, surf the web, compose texts, interact with applications, and so on.

However, conventional techniques that are made available to mobile computing devices to connect accessory devices may consume significant amounts of power, which may hinder the mobility of the device. Further, these conventional techniques could in some instances involve a complicated process by which the accessory device is recognized by the computing device, which could interfere with a user's experience with the device.

SUMMARY

An accessory device architecture is described. In one or more implementations, data is received from an accessory device at an intermediate processor of a computing device, the data usable to enumerate functionality of the accessory device for operation as part of a computing device that includes the intermediate processor. The data is passed by the intermediate processor to an operating system executed on processor of the computing device to enumerate the functionality of the accessory device as part of the intermediate processor.

In one or more implementations, an intermediate processor comprises one or more integrated circuits configured to receive a human interface device descriptor from an accessory device via an interface that supports removable physical and communicative coupling to the accessory device and communicate the human interface device descriptor to a processor that is configured to execute an operating system such that the operating system is made aware of functionality of the accessory device as described in the human interface device descriptor.

In one or more implementations, a computing device includes an interface configured to support a removable communicative coupling with an accessory device, a processor configured to execute an operating system, and an intermediate processor communicatively coupled to the interface and the processor, the intermediate processor configured to support a pass through mode in which human interface device reports received by the intermediate processor from the accessory device via the interface are passed to the operating system without modification.

This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The use of the same reference numbers in different instances in the description and the figures may indicate similar or identical items. Entities represented in the figures may be indicative of one or more entities and thus reference may be made interchangeably to single or plural forms of the entities in the discussion.

FIG. 1 is an illustration of an environment in an example implementation that is operable to employ the techniques described herein.

FIG. 2 is an illustration of an example implementation showing an architecture employable by a computing device and accessory device of FIG. 1.

FIG. 3 is an example implementation of an architecture showing a transport mechanism to support a communicative coupling in greater detail.

FIG. 4 is an example implementation of an architecture showing a configuration of data of FIG. 2 as in compliance with human interface device formats transported via the transport mechanism of FIG. 3.

FIG. 5 is a flow diagram depicting a procedure in an example implementation in which HID descriptors and HID reports are communicated using a pass through mode by an intermediate processor between a processor of a computing device and an accessory device.

FIG. 6 illustrates an example system including various components of an example device that can be implemented as any type of computing device as described with reference to FIGS. 1-5 to implement embodiments of the techniques described herein.

DETAILED DESCRIPTION

Overview

Conventional techniques were developed to allow users to simply attach accessory devices for interaction with a computing device, such as input devices, storage devices, peripheral devices, and so on. However, these conventional techniques could consume significant amounts of power. Consequently, additional techniques were developed to address these shortcomings, but these techniques could limit functionality that was made available to the accessory device, could result in increased resource utilization on the part of the computing device to interact with the accessory device, and so on.

Techniques are described that involve accessory device architectures. In one or more implementations, an architecture may be configured to employ an intermediate processor that is disposed between a processor of the computing device and functionality of the accessory device, e.g., a controller of the accessory device. The intermediate processor may be configured to reduce power consumption of the computing device, such as to permit operation of sensors without waking the processor of the computing device that executes the operating system and so on. 100171 In order to promote flexibility of the architecture, the intermediate processor may support a pass through mode in which data is passed between the accessory device and the operating system without modification by the intermediate processor. In this way, the intermediate processor may support functionality of a wide range of accessory devices without performing updates to firmware of the intermediate processor.

The architecture may also be configured to support techniques to enumerate the accessory device in a manner that mimics plug-and-play functionality without encountering the drawbacks of conventional techniques, such as power consumption as described above. This may be performed by utilizing a communication technique that consumes less power (e.g., through clocking, lower power consumption when operational, and so on) than conventional techniques, although these techniques may also be support in other implementations. This communication technique may further be configured through the architecture to support human interface device (HID) reports such that functionality of the accessory interface device may be enumerated (e.g., via an HID table) to support a consistent technique in which accessory devices having different functionality may interact with the computing device. In this way, an operating system may be made aware of functionality of the accessory device without drawbacks of conventional transport techniques. Further description of these and other techniques may be found in relation to the following sections.

In the following discussion, an example environment is first described that may employ the techniques described herein. Example procedures are then described which may be performed in the example environment as well as other environments. Consequently, performance of the example procedures is not limited to the example environment and the example environment is not limited to performance of the example procedures.

Example Environment

FIG. 1 is an illustration of an environment 100 in an example implementation that is operable to employ the techniques described herein. The illustrated environment 100 includes an example of a computing device 102 that is physically and communicatively coupled to an accessory device 104 via a flexible hinge 106. The computing device 102 may be configured in a variety of ways. For example, the computing device 102 may be configured for mobile use, such as a mobile phone, a tablet computer as illustrated, and so on. Thus, the computing device 102 may range from full resource devices with substantial memory and processor resources to a low-resource device with limited memory and/or processing resources. The computing device 102 may also relate to software that causes the computing device 102 to perform one or more operations.

The computing device 102, for instance, is illustrated as including an input/output module 108. The input/output module 108 is representative of functionality relating to processing of inputs and rendering outputs of the computing device 102. A variety of different inputs may be processed by the input/output module 108, such as inputs relating to functions that correspond to keys of the accessory device 104, keys of a virtual keyboard displayed by the display device 110 to identify gestures and cause operations to be performed that correspond to the gestures that may be recognized through the accessory device 104 and/or touchscreen functionality of the display device 110, and so forth. Other input devices are also contemplated, such as a mouse, track pad, camera to detect gestures, and so on. Thus, the input/output module 108 may support a variety of different input techniques by recognizing and leveraging a division between types of inputs including key presses, gestures, and so on.

In the illustrated example, the accessory device 104 is configured as a keyboard having a QWERTY arrangement of keys although other arrangements are also contemplated, such as storage devices, peripheral devices, output devices, and so on. Further, other non-conventional configurations are also contemplated, such as a game controller, configuration to mimic a musical instrument, and so forth. Thus, the accessory device 104 and keys incorporated by the accessory device 104 may assume a variety of different configurations to support a variety of different functionality.

As previously described, the accessory device 104 is physically and communicatively coupled to the computing device 102 in this example through use of a flexible hinge 106, although other examples are also contemplated such as a wireless connection. The flexible hinge 106 is flexible in that rotational movement supported by the hinge is achieved through flexing (e.g., bending) of the material forming the hinge as opposed to mechanical rotation as supported by a pin, although that embodiment is also contemplated. Further, this flexible rotation may be configured to support movement in one direction (e.g., vertically in the figure) yet restrict movement in other directions, such as lateral movement of the accessory device 104 in relation to the computing device 102. This may be used to support consistent alignment of the accessory device 104 in relation to the computing device 102, such as to align sensors used to change power states, application states, and so on.

The flexible hinge 106, for instance, may be formed using one or more layers of fabric and include conductors formed as flexible traces to communicatively couple the accessory device 104 to the computing device 102 and vice versa. This communication, for instance, may be used to communicate a result of a key press to the computing device 102, receive power from the computing device, perform authentication, provide supplemental power to the computing device 102, and so on.

FIG. 2 depicts an example implementation showing an architecture 200 employable by the computing device 102 and the accessory device 104 of FIG. 1. The illustrated architecture 200 includes a processor 202 and an intermediate processor 204 of a computing device 102 that is communicatively coupled to a controller 206 of the accessory device via an interface 208. The processor 202 may be configured to provide primary processing resources of the computing device 102, such as to execute an operating system, applications, and other software of the computing device 102. Consequently, the processor 202 may consume significant amounts of power, relatively, when in an active state as opposed to a sleep state.

In order to reduce power consumed by the processor 202, the architecture 200 may employ an intermediate processor 204. The intermediate processor 204 may be configured to provide a variety of different functionality, such as to provide functionality while the processor 202 is in a sleep state. This functionality, for instance, may include communication with one or more sensors 210 of the computing device 102 without communication through the processor 202. The intermediate processor 204 may leverage this communication to support waking of the accessory device 104, processor 202, and so on. Thus, these components and devices may remain in a sleep state until a determination is made by the intermediate processor 204 to “wake” these components and devices, thereby conserving power. A variety of other examples are also contemplated without departing from the spirit and scope thereof.

In one or more implementations, the intermediate processor 204 is enumerated to an operating system executed on the processor 202 and thus is “viewable” by the operating system. The intermediate processor 204 may also be configured to communicate with the accessory device 104, e.g., a controller 206, through an interface 208. The accessory device 104, for instance, may be removably physically coupled to the interface 208 of the computing device 102, which may be used to support a communicative coupling such that data 212 may be communicated between the computing device 102 and the accessory device 104. The transport mechanism (e.g., the communicative coupling) and data 212 communicated via this transport mechanism may take a variety of different configurations, an example of which is shown in relation to FIG. 3.

FIG. 3 is an example implementation of an architecture 300 showing a transport mechanism to support a communicative coupling in greater detail. In the illustrated example, the architecture 300 employs a transport mechanism that is configured to consume less power than conventional transport mechanisms. An example of such a mechanism is an I²C interface 302 (i.e., Inter-Integrated Circuit), which may be configured to consume less power than conventional transport mechanisms. For example, the I²C interface 302 may be configured as a transport mechanism that consumes 1.8 volts versus 5 volts and over in conventional mechanisms. This I²C interface 302 may also be configured to reduce power consumption through clocking, in which the mechanism is clocked when actively engaged in transport but is not otherwise as opposed to conventional techniques in which clocking is performed continuously. Other examples are also contemplated, such as to support clock stretching

In the illustrated example, the I²C interface 302 is implemented using three wires or less, which include two data communication lines and a ground to support communication between the processor 202 and intermediate processor 204. This simplifies implementation of this transport mechanism as opposed to conventional transport mechanisms, thereby reducing manufacturing and assembly processes and reducing costs. A UART interface 304 is shown as communicatively coupling the intermediate processor 204 to the controller 206. Other transport mechanisms are also contemplated without departing from the spirit and scope thereof which may consume higher or lower amounts of power. Naturally, a variety of other implementations are also contemplated which may incorporate similar functionality. Regardless of a transport mechanism utilized, data communicated via the mechanism may be configured in a variety of different ways, an example of which is described in relation to the following figure.

FIG. 4 is an example implementation of an architecture 400 showing a configuration of data of FIG. 2 as in compliance with human interface device formats transported via a transport mechanism. Data communicated between the accessory device 104 and the computing device 102 may be configured in a variety of ways to support a variety of functionality. In the illustrated example, the data 208 is configured in accordance with human interface device formats to enumerate, denumerate, and other permit communication between the accessory device 104 and the computing device 102 over I²C interface 302, although other interfaces are also contemplated.

For example, the controller 206 of the accessory device 104 may “talk” with the processor 202 through the intermediate processor 204 using I²C as previously described. This may make it appear that the accessory device 104 is communicatively connected to the processor 202. For instance, from an operating system's point of view that is executed on the processor 202, the enumeration and denumeration of the accessory device 104 may be performed as if the accessory device 104 was physically connected to the processor 202, even though it is not.

Human interface device (HID) references a type of communication that may support bidirectional communication between the accessory device 104 and the computing device 102. HID may be implemented as a self-describing protocol in which packages communicated between the devices may include a variety of different data types and formats, which may be described as part of the communication.

An HID descriptor 402, for instance, may be communicated from the controller 206 of the accessory device 104 it the computing device 102. The HID descriptor 402 may be configured as an array of bytes that describes data packets that are to be communicated between the accessory device 104 and the computing device 102. For example, the HID descriptors 402 may describe functionality that is supported by the accessory device 104 and how interaction with that functionality is to be performed. The HID descriptor 402 may then be parsed by the computing device 102 (e.g., through execution of an operating system) to determine how to interpret data received from the accessory device 104 as well as how to communicate with the accessory device 104.

For example, the HID descriptors 402 may be configured as device descriptors or report descriptors that are stored in firmware of the device. A report descriptor is information describing a format of data that the accessory device 104 is to send to the computing device as well as data that may be sent to the accessory device 104. A device descriptor is information describing functionality available from the accessory device 104, such as input functionality and types (e.g., keys, mouse), and so forth.

Thus, these types of descriptors may be used to report the type of device it is, version information, vendor identifier, product identifier, and other information that is usable by the computing device 102, and more particularly an operating system of the computing device 102, to enumerate and denumerate the device as if it were inherently a plug and play device. Data may then be communicated between the devices (e.g., in the form of HID reports) in accordance with the descriptors, such as in response to inputs, from sensors 210 through the intermediate processor 204 to the controller 206 of the accessory device 104, and so on. Thus, the reports may describe inputs initiated by the accessory device 104, as well as data originating from the computing device 102 to be communicated to the accessory device 104.

The intermediate processor 204 may be configured to support a pass through mode 404 in which data received by the intermediate processor 204 from the controller 206 of the accessory device 104 is passed to the processor 202 without modification. In this way, the intermediate processor 204 may be configured to address a variety of different accessory devices 104, even devices having functionality that will be made available in the future, without updating the intermediate processor 204.

For example, HID reports (e.g., HID mouse report and HID keyboard report) are passed from the accessory device 104 through the intermediate processor 204 to the processor 202 in the pass through mode 404. Reports from the accessory device 104 may be packaged in such a way as to be consumable by the computing device 102 without additional modification by the intermediate processor 204. This provides support of future accessory devices without a firmware modification to the intermediate processor 204 each time a new accessory device is released. Also, this provides a standard specification by which future accessory devices pass information to the host.

The intermediate processor 204 may be configured to support a variety of other functionality. For example, the accessory device 104 may not able to manage its own power without information from the intermediate processor 204. Because of this, the intermediate processor 204 may be implemented to manage power of the accessory device 104. In another example, the accessory device 104 and the intermediate processor 204 may manage power using interfaces. The accessory device 104, for instance, may register with the intermediate processor 204.

This registration may be performed to cause reports to be sent from the intermediate processor 204 to the controller 206 of the accessory device 104. The reports, for instance, may include values from the sensors 210, such as when values of an accelerometer change by a certain level (e.g., above a threshold) in a defined amount of time. This alleviates the intermediate processor 204 from managing the power of each accessory device and is a cleaner solution in instances in which the accessory device 104 has increased knowledge on how to manage its own power. A variety of other examples are also contemplated, such as to report status that is used by the accessory device 104 to determine what power state in which to place the accessory device 104.

Example Procedure

The following discussion describes accessory device architecture techniques that may be implemented utilizing the previously described systems and devices. Aspects of each of the procedures may be implemented in hardware, firmware, or software, or a combination thereof. The procedures are shown as a set of blocks that specify operations performed by one or more devices and are not necessarily limited to the orders shown for performing the operations by the respective blocks. In portions of the following discussion, reference will be made to FIGS. 1-4.

FIG. 5 depicts a procedure 500 in an example implementation in which HID descriptors and HID reports are communicated using a pass through mode by an intermediate processor between a processor of a computing device and an accessory device. Data is received from an accessory device at an intermediate processor of a computing device, the data usable to enumerate functionality of the accessory device for operation as part of a computing device that includes the intermediate processor (block 502). The data, for instance, may be configured as one or more HID descriptors that may be used to enumerate the accessory device 104. This may include device and report descriptors as previously described to self-described the device in a standardized way.

The data may be passed by the intermediate processor to an operating system executed on a processor of the computing device to enumerate the functionality of the accessory device (block 504). This may include enumeration of the functionality as part of the intermediate processor 204, enumeration such that the accessory device 104 is enumerated by the intermediate processor 204 is not, and so on. Thus, the descriptors may be leveraged to provide a technique that is flexible in describing functionality that is available from the accessory device 104.

Additionally, in one or more implementations the intermediate processor 204 is enumerated as a device by the operating system such that the intermediate processor 204 is viewable by the operating system. However, in some instances the operating system may not recognize additional devices that are coupled to that device, and thus may not be able to recognize the accessory device 104. Accordingly, in such an instance the functionality of the accessory device 104 may be enumerated as part of the intermediate processor 204 such that this functionality is made available to the operating system. Thus, in this instance the accessory device 104 is not enumerated as a separate device itself in addition to the intermediate processor 204. Other examples are also contemplated in which separate enumeration is performed.

Example System and Device

FIG. 6 illustrates an example system generally at 600 that includes an example computing device 602 that is representative of one or more computing systems and/or devices that may implement the various techniques described herein. The computing device 602 may be, for example, be configured to assume a mobile configuration through use of a housing formed and size to be grasped and carried by one or more hands of a user, illustrated examples of which include a mobile phone, mobile game and music device, and tablet computer although other examples are also contemplated.

The example computing device 602 as illustrated includes a processing system 604, one or more computer-readable media 606, and one or more I/O interface 608 that are communicatively coupled, one to another. Although not shown, the computing device 602 may further include a system bus or other data and command transfer system that couples the various components, one to another. A system bus can include any one or combination of different bus structures, such as a memory bus or memory controller, a peripheral bus, a universal serial bus, and/or a processor or local bus that utilizes any of a variety of bus architectures. A variety of other examples are also contemplated, such as control and data lines.

The processing system 604 is representative of functionality to perform one or more operations using hardware. Accordingly, the processing system 604 is illustrated as including hardware element 610 that may be configured as processors, functional blocks, and so forth. This may include implementation in hardware as an application specific integrated circuit or other logic device formed using one or more semiconductors. The hardware elements 610 are not limited by the materials from which they are formed or the processing mechanisms employed therein. For example, processors may be comprised of semiconductor(s) and/or transistors (e.g., electronic integrated circuits (ICs)). In such a context, processor-executable instructions may be electronically-executable instructions.

The computer-readable storage media 606 is illustrated as including memory/storage 612. The memory/storage 612 represents memory/storage capacity associated with one or more computer-readable media. The memory/storage component 612 may include volatile media (such as random access memory (RAM)) and/or nonvolatile media (such as read only memory (ROM), Flash memory, optical disks, magnetic disks, and so forth). The memory/storage component 612 may include fixed media (e.g., RAM, ROM, a fixed hard drive, and so on) as well as removable media (e.g., Flash memory, a removable hard drive, an optical disc, and so forth). The computer-readable media 606 may be configured in a variety of other ways as further described below.

Input/output interface(s) 608 are representative of functionality to allow a user to enter commands and information to computing device 602, and also allow information to be presented to the user and/or other components or devices using various input/output devices. Examples of input devices include a keyboard, a cursor control device (e.g., a mouse), a microphone, a scanner, touch functionality (e.g., capacitive or other sensors that are configured to detect physical touch), a camera (e.g., which may employ visible or non-visible wavelengths such as infrared frequencies to recognize movement as gestures that do not involve touch), and so forth. Examples of output devices include a display device (e.g., a monitor or projector), speakers, a printer, a network card, tactile-response device, and so forth. Thus, the computing device 602 may be configured in a variety of ways to support user interaction.

The computing device 602 is further illustrated as being communicatively and physically coupled to an input device 614 that is physically and communicatively removable from the computing device 602. In this way, a variety of different input devices may be coupled to the computing device 602 having a wide variety of configurations to support a wide variety of functionality. In this example, the input device 614 includes one or more keys 616, which may be configured as pressure sensitive keys, mechanically switched keys, and so forth.

The input device 614 is further illustrated as include one or more modules 618 that may be configured to support a variety of functionality. The one or more modules 618, for instance, may be configured to process analog and/or digital signals received from the keys 616 to determine whether a keystroke was intended, determine whether an input is indicative of resting pressure, support authentication of the input device 614 for operation with the computing device 602, and so on.

Various techniques may be described herein in the general context of software, hardware elements, or program modules. Generally, such modules include routines, programs, objects, elements, components, data structures, and so forth that perform particular tasks or implement particular abstract data types. The terms “module,” “functionality,” and “component” as used herein generally represent software, firmware, hardware, or a combination thereof. The features of the techniques described herein are platform-independent, meaning that the techniques may be implemented on a variety of commercial computing platforms having a variety of processors.

An implementation of the described modules and techniques may be stored on or transmitted across some form of computer-readable media. The computer-readable media may include a variety of media that may be accessed by the computing device 602. By way of example, and not limitation, computer-readable media may include “computer-readable storage media” and “computer-readable signal media.”

“Computer-readable storage media” may refer to media and/or devices that enable persistent and/or non-transitory storage of information in contrast to mere signal transmission, carrier waves, or signals per se. Thus, computer-readable storage media refers to non-signal bearing media. The computer-readable storage media includes hardware such as volatile and non-volatile, removable and non-removable media and/or storage devices implemented in a method or technology suitable for storage of information such as computer readable instructions, data structures, program modules, logic elements/circuits, or other data. Examples of computer-readable storage media may include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical storage, hard disks, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or other storage device, tangible media, or article of manufacture suitable to store the desired information and which may be accessed by a computer.

“Computer-readable signal media” may refer to a signal-bearing medium that is configured to transmit instructions to the hardware of the computing device 602, such as via a network. Signal media typically may embody computer readable instructions, data structures, program modules, or other data in a modulated data signal, such as carrier waves, data signals, or other transport mechanism. Signal media also include any information delivery media. The term “modulated data signal” means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media include wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, RF, infrared, and other wireless media.

As previously described, hardware elements 610 and computer-readable media 606 are representative of modules, programmable device logic and/or fixed device logic implemented in a hardware form that may be employed in some embodiments to implement at least some aspects of the techniques described herein, such as to perform one or more instructions. Hardware may include components of an integrated circuit or on-chip system, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a complex programmable logic device (CPLD), and other implementations in silicon or other hardware. In this context, hardware may operate as a processing device that performs program tasks defined by instructions and/or logic embodied by the hardware as well as a hardware utilized to store instructions for execution, e.g., the computer-readable storage media described previously.

Combinations of the foregoing may also be employed to implement various techniques described herein. Accordingly, software, hardware, or executable modules may be implemented as one or more instructions and/or logic embodied on some form of computer-readable storage media and/or by one or more hardware elements 610. The computing device 602 may be configured to implement particular instructions and/or functions corresponding to the software and/or hardware modules. Accordingly, implementation of a module that is executable by the computing device 602 as software may be achieved at least partially in hardware, e.g., through use of computer-readable storage media and/or hardware elements 610 of the processing system 604. The instructions and/or functions may be executable/operable by one or more articles of manufacture (for example, one or more computing devices 602 and/or processing systems 604) to implement techniques, modules, and examples described herein.

Conclusion

Although the example implementations have been described in language specific to structural features and/or methodological acts, it is to be understood that the implementations defined in the appended claims is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as example forms of implementing the claimed features. 

What is claimed is:
 1. A computing device comprising: a processing system configured to execute an operating system for the computing device: an interface connectable to an accessory device; and an integrated circuit device connected to the processing system and the interface, the integrated circuit device configured to: operate when the processing system is in a low power state; and enumerate functionality of the accessory device by: receiving descriptors indicative of functionality of the accessory device from the accessory device via the interface; and communicating with the operating system to pass information regarding the functionality of the accessory device as indicated by the descriptors for use by the operating system to enable communications with the accessory device via the integrated circuit device.
 2. A computing device as described in claim 1, wherein the functionality of the accessory device is communicated to the operating system as functionality of the integrated circuit device so that the accessory device is invisible to the operating system.
 3. A computing device as described in claim 1, wherein the functionality of the accessory device is communicated to the operating system as functionality of a separate device so that the accessory device is viewable by the operating system.
 4. A computing device as described in claim 1, wherein the integrated circuit device is configured to receive a report indicating a status of the accessory device and configured to manage power of the accessory device based on the indicated status.
 5. A computing device as described in claim 1, wherein the integrated circuit device is configured to provide reports to the accessory device that cause the accessory device to perform power management.
 6. A computing device as described in claim 1, wherein the integrated circuit device is connected to the processing system via a transport mechanism that performs clocking when transporting data between the integrated circuit device and the processing system but does not perform clocking otherwise.
 7. A computing device as described in claim 1, wherein the descriptors indicative of functionality of the accessory device identify a data format for use in communications between the computing device and the accessory device.
 8. A computing device as described in claim 1, wherein the descriptors indicative of functionality of the accessory device identify a device type of the accessory device.
 9. A computing device as described in claim 1, wherein the descriptors indicative of functionality of the accessory device include one or more of a vendor identifier (VID) of the accessory device or a product identifier (PID) of the accessory device.
 10. A computing device as described in claim 1, wherein the descriptors indicative of functionality of the accessory device identify a version of the accessory device.
 11. A method comprising: receiving, at an integrated circuit device of a computing device, information that is indicative of functionality of an accessory device connected to the integrated circuit device; passing, via the integrated circuit device to an operating system executing on a processing system of the computing device, information indicative of the functionality of the accessory device; and enabling, via the integrated circuit device, communication between the operating system and the accessory device based on the functionality of the accessory device.
 12. A method as described in claim 11, wherein the receiving, the passing, and the enabling are performed by the integrated circuit device while the processing system of the computing device is in a low power state.
 13. A method as described in claim 11, wherein the passing is performed by the integrated circuit device without modifying the information indicative of functionality of the accessory device.
 14. A method as described in claim 11, further comprising receiving, by the integrated circuit device, a report indicating a status of the accessory device and managing power of the accessory device based on the indicated status.
 15. A method as described in claim 11, wherein the information indicative of functionality of the accessory device identifies one or more of: a data format for use in communications between the computing device and the accessory device; a device type of the accessory device; a vendor identifier (VID) of the accessory device; a product identifier (PID) of the accessory device; a version of the accessory device.
 16. A communication circuit configured to: receive descriptors indicative of functionality of an accessory device via an interface of a computing device that supports a removable physical and communicative coupling between the computing device and the accessory device; communicate, with an operating system executed on a processor of the computing device, to pass information regarding the functionality of the accessory device as indicated by the descriptors for use by the operating system to enable communications with the accessory device via the communication circuit; and operate when the processor of the computing device is in a low power state.
 17. A communication circuit as described in claim 16, wherein the functionality of the accessory device is: communicated to the operating system as functionality of the communication circuit so that the accessory device is invisible to the operating system; or communicated to the operating system as functionality of a separate device so that the accessory device is viewable by the operating system.
 18. A communication circuit as described in claim 16, wherein the communication circuit is configured to receive a report indicating a status of the accessory device and configured to manage power of the accessory device based on the indicated status.
 19. A communication circuit as described in claim 16, wherein the communication circuit is configured to operate when the processor of the computing device is in a low power state.
 20. A communication circuit as described in claim 16, wherein the communication circuit is communicatively coupled to the processor via a transport mechanism that performs clocking when transporting data between the communication circuit and the processor but does not perform clocking otherwise. 